The eastern woodchuck (Marmota monax) infected by the Woodchuck Hepatitis Virus (WHV) is a well-characterized infection model paralleling the disease processes of human hepatitis B virus infection The AALAC-accredited colony at Cornell is entirely house bred according to genealogy thus preventing the potential anomalies of using wild-caught animals. As such it is considered the "gold standard" model in which to test new and established antiviral agents both singly and in combination. It is also used as a model to identify both viral and host responses to infection, pathogenesis, immune responses, and viral resolution. Promising candidate antivirals tested initially in well-defined in vitro screens can subsequently move into in vivo testing through the HBV Animal Model Network-a consortium of three contracts involved in this endeavor.